Articles of footwear generally include two primary elements, an upper and a sole structure. The upper is often formed from a plurality of elements (e.g., textiles, foam, leather, synthetic leather) that are stitched or adhesively bonded together to form an interior void for securely and comfortably receiving a foot. The sole structure is secured to a lower areas of the upper and effectively extends between the foot and the ground.
Depending upon the intended use for an article of footwear, the overall configuration of the upper and the sole structure may vary considerably. For example, footwear utilized for running (i.e., jogging) may incorporate a compressible and flexible sole structure, which is often formed from a polymer foam material, and may also include a variety of additional footwear elements that enhance the comfort or performance of the footwear, including moderators, fluid-filled chambers, lasting elements, or motion control members. Footwear utilized for sprinting may also impart some compressibility, but sometimes has a low-profile and stiffer configuration that is beneficial during a sprint. Other articles of footwear, such as cycling shoes, may benefit from more rigid configurations. Cycling shoes are utilized during cycling competitions, training sessions, and recreational rides to interface with bicycle pedals. In order to efficiently transfer energy from a rider to the pedals, cycling shoes often incorporate rigid plates and mounting hardware for a cleat or other device that interfaces with the pedals. Snowboarding, skiing, and motorcycle boots may also incorporate rigid sole structures. Accordingly, depending upon the intended purpose for an article of footwear, the sole structure may range from compliant and compressible to rigid.